Sunday, February 23, 2014

Ben Jones writes about the simplistic GDP map

The silly map that I critiqued the other day has led to an alluring conversation about the virtues of clarity and depth versus mere simplification in information graphics. In one of the comments, I asked readers to look for more data on the relationship between population density and GDP generation. DataRemixed's Ben Jones has just replied. I am copying what he wrote in the original post. This is the kind of exploration and analysis work that is missing in the simplistic map that spurred the discussion. Visit all the links. Here's Ben:

Some notes: Unfortunately, the U.S. doesn't publish GDP at a county level, only by state and metro area, so I used IRS income tax data instead to answer the question "are financial maps just population maps?" Spoiler: yes, unless you look at per capita figures (hat tip to Kosara).

A caveat: What's interesting to me about the original project that the stirred the debate isn't the absolute concentration of the source of GDP. We all knew it would center on NYC, LA, Dallas, Chicago, etc, etc. What's interesting is the question of concentration of GDP relative to concentration of population. Is the GDP "over-indexed" for these places or not? If we ask this question of the IRS income data, we can see there is a small degree of over-indexing: of the 100 or so counties that account for 50% of the Adjusted Gross Income in 2011, 42% of the overall population of the country lives there. This cumulative distribution chart helps answer that question.